Modified High Performance Concrete
Influence of MB modifiers on properties of concretes and concrete mixtures
Heavy-weight and fine-grained concrete properties
Properties of structural light-weight concretes
Mechanism of MB action on cement systems
Characteristic features of MB concrete proportioning
MBЦ01, ћB-— or Embelit modifiers.
Ordinary Portland cement M400 or M500 according to the Russian Standard in the amount not exceeding 500 kg/m3.
Light-weight gravel with compressive strength of 2Е10 ћPа and bulk weight 500Е800 kg/m3.
High performance - are concretes of high strength, low permeability, high corrosion resistance and durability, with compensated shrinkage or expansion, i.e. they possess such qualities the combination or prevalence of which provides a high reliability of structures depending on utilization conditions [46, 47, 64, 75, 82, 89, 90, 91].
The application of such concretes in most cases allows to avoid a Ђsecondaryї corrosion protection (protective coatings).
Main concrete properties
Compressive strength ranges from 40 to 120 MPa for heavy-weight and fine-grained concrete which corresponds to classes B30ЕB100.
Compressive strength ranges from 40 to 80 MPa for structural light-weight concrete with density grade D1600ЕD1800 kg/m3, which corresponds to classes B30ЕB60.
Range of short-term and long-term deformation characteristics:
- for concrete classes up to B60 (compressive strength up to 80 MPa) Ц according to the existing Russian State Norms and Rules for designing reinforced concrete structures (SNiP 2.03.01-84 and SNiP 2.05.03-84);
- for concrete classes over B60 (over 80 MPa) Ц special norms are applied .
Compressive strength range at normal curing within 24 hours Ц 25Е40 MPa.
The level of deformations due to shrinkage is 0.02Е0.1% and the value of self-stress - 0.5Е3.0 ћPа.
Low permeability to water, gas and chlorides: the water tightness grade exceeds W12ЕW20;
Frost resistance not lower than that of ordinary concretes. With additional use of air entraining or gas forming admixtures can be dramatically increased to grades F700ЕF1000.
Resistance without a protective coating in the following environments:
- in weak acid environments with pH>3;
- in gas environments with the concentration of corrosive gas one step higher than the existing Russian norms and rules for corrosion protection in structural design (SNiP 2.03.11Ц85);
- in liquid environments with the concentration of chlorides and sulfates one step higher than the existing Russian norms and rules for corrosion protection in structural design (SNiP 2.03.11Ц85).
Increased thixotropy and long-term stability of concrete mixtures, including self compacting which are not subject to segregation.